The field of the invention is that of lubricating systems for engines. More specifically, the field of the invention is lubricating systems for shaft bearings in vertical shaft engines.
Effective oil lubrication systems for lubricating the working components of an internal combustion engine are necessary to prevent bearing failure and to increase the life of the engine by reducing engine wear. In vertical shaft engines, the bearings for the lower ends of shaft journals must be adequately lubricated. Lubrication systems supply the oil by either a high pressure circulating system or a gravity based sump system.
In a high pressure circulating system, oil circulates within circuits of the system to provide lubrication to each bearing. However, the system of tubing and passageways required for a high pressure system unduly complicates an engine, and greatly adds to its manufacturing cost.
In sump systems, generally oil is splashed or sprayed by displacement pumps and the oil eventually drains back by the force of gravity to an oil pool. The oil pool, or sump, at the bottom of the crankcase provides an oil reservoir for the displacement pumps, but providing displacement pumps requires complex and expensive alterations to the engine design. Also, the lower shaft bearings can be immersed in oil of the sump, so that the oil does not have to be supplied to the bearings by a separate device.
Under normal conditions, when the oil sump is full and the crankcase is level, the immersion lubrication system for shaft journals works correctly. However, if the oil level drops or the crankcase is tilted, often no oil is available for lubricating the bearings. This results from the intake line of the displacement pump being above the oil level position in the crankcase sump. A relatively minor drop in oil level may cause the bearing wall to extend above the oil sump's level, or a tilting may cause the oil to drain into a different part of the engine crankcase.
What is needed to overcome the above problems is an oil lubrication system which provides self-lubrication for shaft bearings. Also needed is a lubrication system which can supply lubrication when the oil sump is at a fractional level or when it is tilted. Yet another need is for a lubrication system which is simple and inexpensive to manufacture.